Re: EHP External Hardware Proposal

Fred Smith wrote:

> I guess I missed the previous Postings. Here is the standard:
>
> : ANSI/EIA 274-D-1980 (R1988): Interchangeable
> Variable Block Data Format for Positioning, Contouring, and
> Contouring/Positioning Numerically Controlled Machines.
>
> Here is an interesting link from a school with lots of nice pictures
> and words about CNC (they have a copy of the standard in their
> library):
>
> http://iesu5.ieem.ust.hk/dfaculty/ajay/courses/ieem215/lecs/CNC.html
>

I looked at this, and found one glaring error pretty quickly.

"In practice, the BLU is equivalent to the accuracy of the machine
tool."
[ BLU it their term for encoder or stepper resolution.]

Anyway, having a copy of the RS-274D standard in a library 10,000 miles
from me is not
a great help. I was hoping that you meant it was accessible from their
web page, but I don't
think so.

Anyway, it does have some examples of NC programming, with arcs.

Jon